Century Arms RI4090-N RI4090N: Century Arms's heavy-duty AK-47 rifle. This particular VSKA has been re-engineered from top to bottom and is incredibly reliable. The VSKA rifle features a bolt carrier, front trunnion, and feed ramp machined manufactured from S7 tool steel and comes specially heat-treated for maximum durability. The front trunnion and bolt are machined from billet and exceeded the durability goals for the project. Additionally, the VSKA features a carburized 4140 steel bolt, a chrome-moly 4150 barrel, and sports the RAK-1 Enhanced Trigger Group for an impressive trigger pull. This model comes standard with a manganese-phosphate finish and polymer buttstock.